scholarly journals Analytical modeling of mine water rebound: Three case studies in closed hard-coal mines in Germany

2021 ◽  
Vol 15 (3) ◽  
pp. 22-30
Author(s):  
Dmytro Rudakov ◽  
Sebastian Westermann
Keyword(s):  
Hydraulic Conductivity ◽  
Analytical Model ◽  
Water Flow ◽  
Mine Water ◽  
Input Data ◽  
Analytical Modeling ◽  
Coal Mines ◽  
Hard Coal ◽  
Preliminary Evaluation ◽  
Working Volume

Purpose.In this paper we present and validate an analytical model of water inflow and rising level in a flooded mine and examine the model robustness and sensitivity to variations of input data considering the examples of three closed hard-coal mines in Germany. Methods. We used the analytical solution to a boundary value problem of radial ground water flow to the shaft, treated as a big well, and water balance relations for the series of successive stationary positions of a depression cone to simulate a mine water rebound in the mine taking into account vertical distribution of hydraulic conductivity, residual volume of underground workings, and natural pores. Findings. The modeling demonstrated very good agreement with the measured data for all the studied mines. The maximum relative deviation for the mine water level during the measurement period did not exceed 2.1%; the deviation for the inflow rate to a mine before its flooding did not exceed 0.8%. Sensitivity analysis revealed the higher significance of the residual working volume and hydraulic conductivity for mine water rebound in the case of thick overburden and the growing significance of the infiltration rate and the flooded area size in the case of lower overburden thickness. Originality.The developed analytical model allows realistic prediction of transient mine water rebound and inflow into a mine with layered heterogeneity of rocks, irregular form of the drained area, and with the inflow/outflow to a neighboring mine and the volume of voids as a distributed parameter without gridding the flow domain performed in numerical models. Practical implications.The study demonstrated the advantages of analytical modeling as a tool for preliminary evaluation and prediction of flooding indicators and parameters of mined out disturbed rocks. In case of uncertain input data, modeling can be considered as an attractive alternative to usually applied numerical methods of modeling ground and mine water flow.

scholarly journals Closure of German Hard Coal Mines: Effects and Legal Aspects of Mine Flooding

2021 ◽  
Author(s):  
Marion Stemke ◽  
Georg Wieber
Keyword(s):  
Water Level ◽  
Mine Water ◽  
National Level ◽  
Coal Mines ◽  
Legal Aspects ◽  
Hard Coal ◽  
Water Protection ◽  
The European Union ◽  
Mine Flooding ◽  
Approval Procedure

AbstractFollowing the closure of the last hard coal mines in Germany, pumping is no longer necessary. However, the resulting rise of mine water can affect the environment. Laws have been enacted at the European and national level to protect properties. Within the framework of the approval procedure, it must be determined whether the cessation of pumping may cause unacceptable effects, including water pollution. With regard to water protection, the European Union has issued the Water Framework and Groundwater Directives, which have been implemented into German national law. These contain the prohibition of deterioration and the requirement for improvement, with the aim of maintaining or achieving good ecological and chemical status. However, before the target mine water level is reached, the water does not need to comply, since although the pumps are switched off, no mine water is being discharged. This also rules out permit requirements, which only go into effect when the target mine water level has been reached and mine water is discharging. Obviously, however, detailed planning before then is necessary.

Radiological evaluation of mine water discharges from hard coal mining in the Fossa Eugeniana Area, Germany

Kerntechnik ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. 101-107
Author(s):  
C. Wanke ◽  
S. Ritzel ◽  
R. Sachse ◽  
R. Michel
Keyword(s):  
Coal Mining ◽  
Mine Water ◽  
Hard Coal ◽  
Radiological Evaluation ◽  
Hard Coal Mining

scholarly journals Innovative Method for Calculating the Break-Even for Multi-Assortment Production

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4213
Author(s):  
Dariusz Fuksa
Keyword(s):  
Coal Mines ◽  
New Method ◽  
Hard Coal ◽  
Customer Demand ◽  
Innovative Method ◽  
The Subject ◽  
Economic Health ◽  
Production Plans ◽  
A Company ◽  
A Current

The subject of the article is a new method that I have developed for calculating a multi-asset break-even for multi-assortment production, extended by a percentage threshold and a current sales ratio (which was missing in previously published methods). The percentage threshold provides unambiguous information about the economic health of a company. As a result, it became possible to use it in practice to evaluate the activities of economic entities (mines) and to perform modelling and optimisation of production plans based on different variants of customer demand scenarios. The publication addresses the complexity of the problem of determining the break-even in multi-assortment production. Moreover, it discusses the practical limitations of previous methods and demonstrates the usefulness of the proposed method on the example of hard coal mines.

scholarly journals Cheating at Craps

2021 ◽  
Vol 48 (4) ◽  
pp. 53-61
Author(s):  
Andrea Marin ◽  
Carey Williamson
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Modeling And Simulation ◽  
Analytical Model ◽  
Quantitative Evaluation ◽  
Mathematical Analysis ◽  
Simulation Modeling ◽  
Analytical Modeling ◽  
The World ◽  
Simulation Results

Craps is a simple dice game that is popular in casinos around the world. While the rules for Craps, and its mathematical analysis, are reasonably straightforward, this paper instead focuses on the best ways to cheat at Craps, by using loaded (biased) dice. We use both analytical modeling and simulation modeling to study this intriguing dice game. Our modeling results show that biasing a die away from the value 1 or towards the value 5 lead to the best (and least detectable) cheating strategies, and that modest bias on two loaded dice can increase the winning probability above 50%. Our Monte Carlo simulation results provide validation for our analytical model, and also facilitate the quantitative evaluation of other scenarios, such as heterogeneous or correlated dice.

scholarly journals Geophysical and analytical determination of overstressed zones in exploited coal seam: a case study

2021 ◽  
Author(s):  
Dariusz Chlebowski ◽  
Zbigniew Burtan
Keyword(s):  
Coal Seam ◽  
Wave Velocity ◽  
Seismic Tomography ◽  
Analytical Modeling ◽  
Coal Mines ◽  
Vertical Stress ◽  
P Wave ◽  
Rockburst Hazard ◽  
State Of Stress ◽  
P Wave Velocity

AbstractA variety of geophysical methods and analytical modeling are applied to determine the rockburst hazard in Polish coal mines. In particularly unfavorable local conditions, seismic profiling, active/passive seismic tomography, as well as analytical state of stress calculating methods are recommended. They are helpful in verifying the reliability of rockburst hazard forecasts. In the article, the combined analysis of the state of stress determined by active seismic tomography and analytical modeling was conducted taking into account the relationship between the location of stress concentration zones and the level of rockburst hazard. A longwall panel in the coal seam 501 at a depth of ca.700 m in one of the hard coal mines operating in the Upper Silesian Coal Basin was a subject of the analysis. The seismic tomography was applied for the reconstruction of P-wave velocity fields. The analytical modeling was used to calculate the vertical stress states basing on classical solutions offered by rock mechanics. The variability of the P-wave velocity field and location of seismic anomaly in the coal seam in relation to the calculated vertical stress field arising in the mined coal seam served to assess of rockburst hazard. The applied methods partially proved their adequacy in practical applications, providing valuable information on the design and performance of mining operations.

Estimating high hydraulic conductivity locations through a 3D simulation of water flow in soil and a resistivity survey

2018 ◽  
Vol 49 (3) ◽  
pp. 299-308 ◽  
Author(s):  
Keisuke Inoue ◽  
Hiroomi Nakazato ◽  
Tomijiro Kubota ◽  
Koji Furue ◽  
Hiroshi Yoshisako ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
3D Simulation ◽  
Resistivity Survey ◽  
High Hydraulic Conductivity

scholarly journals Saturated Hydraulic Conductivity Estimation Using Artificial Neural Networks

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 705
Author(s):  
Josué Trejo-Alonso ◽  
Carlos Fuentes ◽  
Carlos Chávez ◽  
Antonio Quevedo ◽  
Alfonso Gutierrez-Lopez ◽  
...  
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Hydraulic Conductivity ◽  
Input Data ◽  
Logistic Function ◽  
Saturated Hydraulic Conductivity ◽  
Irrigation District ◽  
Pedotransfer Functions ◽  
Back Propagation Algorithm ◽  
Artificial Neural

In the present work, we construct several artificial neural networks (varying the input data) to calculate the saturated hydraulic conductivity (KS) using a database with 900 measured samples obtained from the Irrigation District 023, in San Juan del Rio, Queretaro, Mexico. All of them were constructed using two hidden layers, a back-propagation algorithm for the learning process, and a logistic function as a nonlinear transfer function. In order to explore different arrays for neurons into hidden layers, we performed the bootstrap technique for each neural network and selected the one with the least Root Mean Square Error (RMSE) value. We also compared these results with pedotransfer functions and another neural networks from the literature. The results show that our artificial neural networks obtained from 0.0459 to 0.0413 in the RMSE measurement, and 0.9725 to 0.9780 for R2, which are in good agreement with other works. We also found that reducing the amount of the input data offered us better results.

Mine water hydrogeochemistry of abandoned coal mines in the outcropped Carboniferous formations, Ruhr Area, Germany

2020 ◽  
Vol 79 (4) ◽  
Author(s):  
Tuan Quang Tran ◽  
Andre Banning ◽  
Frank Wisotzky ◽  
Stefan Wohnlich
Keyword(s):  
Mine Water ◽  
Coal Mines ◽  
Ruhr Area ◽  
Abandoned Coal Mines
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